Researchers at MIT—Prof. Daniel Nocera and Dr. Matthew Kanan—have developed a new water-splitting catalyst that is easily prepared from earth-abundant materials (cobalt and phosphorous) and operates in benign conditions: pH neutral water at room temperature and 1 atm pressure. A report on their discovery was published online 31 July 2008 in the journal Science.

The cobalt-phosphorous catalyst targets the generation of oxygen gas from water—the more complex of the two water-splitting half-cell reactions required (H2O/O2 and H2O/H2). Another catalyst generates the hydrogen. Although the new catalyst requires further work, it opens a very promising pathway for the development of systems that use artificial photosynthesis to store solar energy on a large scale in the form of O2 and H2 for subsequent use in a fuel cell.

Of the two reactions, the H2O/O2 reaction is considerably more complex. This reaction requires a four-electron oxidation of two water molecules coupled to the removal of four protons to form a relatively weak oxygen-oxygen bond. In addition to controlling this proton-coupled electron transfer (PCET), a catalyst must tolerate prolonged exposure to oxidizing conditions. Even at the thermodynamic limit, water oxidation requires an oxidizing power that causes most chemical functional groups to degrade. Accordingly, the
generation of oxygen from water presents a significant challenge toward realizing artificial photosynthesis.

—Nocera and Kanan (2008)

Other water oxidation catalysts exist, including first-row spinel and perovskite metal oxides; and precious metals and precious metal oxides. The first requires concentrated basic solutions (pH>13) and moderate overpotentials (<400 mV); the second operate under acidic conditions (pH<1).

However, few catalysts operate under the conditions of photosynthesis, i.e. in neutral water under ambient conditions. Neutral water is oxidized at Pt electrodes and some precious metal oxides have been reported to operate electrocatalytically in neutral or weakly
acidic solutions. The development of an earth-abundant, first-row catalyst that operates at pH 7 at low overpotential remains a fundamental chemical challenge. Here we report an oxygen-evolving catalyst that forms in situ upon anodic polarization of an inert electrode in neutral aqueous
phosphate solutions containing Co2+. Oxygen generation occurs under benign conditions: pH = 7, 1 atm and room temperature.

—Nocera and Kanan (2008)

The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity—whether from a photovoltaic cell, a wind turbine or any other source—runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced. Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

James Barber, a leading researcher in the study of photosynthesis who was not involved in this research, called the discovery by Nocera and Kanan a “giant leap” toward generating clean, carbon-free energy on a massive scale.

This is a major discovery with enormous implications for the future prosperity of humankind. The importance of their discovery cannot be overstated since it opens up the door for developing new technologies for energy production thus reducing our dependence for fossil fuels and addressing the global climate change problem

—James Barber, the Ernst Chain Professor of Biochemistry at Imperial College London

Currently available electrolyzers, which split water with electricity and are often used industrially, are not suited for artificial photosynthesis because they are very expensive and require a highly basic (non-benign) environment that has little to do with the conditions under which photosynthesis operates.

If artificial photosynthesis is to enable the storage of solar energy
commensurate with global demand, water-splitting chemistry will need to be performed at a daunting scale. Storing the equivalent of the current energy demand would require splitting greater than 1015 mol/yr of water, which is roughly 100 times the scale of nitrogen fixation by the Haber Bosch process. [The Haber Bosch process allows the mass synthesis of ammonia from nitrogen and hydrogen.]

The conditions under which water splitting is performed will determine how solar energy is deployed. The catalyst reported here has many elements of natural photosynthesis including its formation from earth abundant metal ions in aqueous solution, a plausible pathway for self-repair, a carrier for protons in neutral water and the generation of O2 at low overpotential, neutral pH, 1 atm and room temperature.

—Nocera and Kanan (2008)

More engineering work needs to be done to integrate the new scientific discovery into existing photovoltaic systems, but Nocera said he is confident that such systems will become a reality. Nocera is the principal investigator for the Solar Revolution Project funded by the Chesonis Family Foundation and co-Director of the Eni-MIT Solar Frontiers Center.

This is just the beginning. The scientific community is really going to run with this.

—Daniel Nocera

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past.

The project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet the needs of the future and to help build a bridge to that future by improving today’s energy systems.

This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years.

Hilarious! This is an "article" written by a character with the nom de plume "JoulesBurn," and published in the cranky online blog site: “The Oil Drum.” It attempts to debunk everything the peer reviewed article published by Journal Science, and its authors from MIT claim. Apparently these bloggers are better informed, more intelligent, non-agenda driven gurus.

What this group of disgruntled wizards dislike is no less than... Progress! Especially technological progress that emanates not from THEIR wizened hands. One might dismiss these curmudgeons as victims of professional jealousy - but their agenda runs deeper than that. They despise no less than any technology that alleviates pain and suffering. For these unhappy souls practice the religion of the infinite less. That is, unless you are made to do, think and use less of matter or material things - they are incensed. For materials things and conveyances are... Evil.

For these, sadly misanthropic beings, life is a scourge, a painful trek across God's land that they and only they wish to be guardians of. You, typical human beings who seek to improve your quality of life, and drink from the well of abundance - are their enemy. And any scientist or technology that might alleviate suffering or extend the ability to live a free and unfettered life, e.g. by way o f low cost, unlimited energy - must be destroyed!

This group worships a single idea: central monopoly. In that idea they believe they can maintain a privileged place of gate-keeping authority. THEY will arbitrate how you use energy, who will produce energy, and where it shall derive from. They are, in fact, people little or no different from the previous ministers of big oil. A small cabal of green priests who lust to control all aspects of new energy - and thereby your life.

But they are also a deeply disturbed clan. Not unlike the stereotyped nerds tottering down the halls of thousands of high schools and colleges. Pocket protector, slide rule fidgeting, nerds. Now grown nerds. Who, having suffered years of humiliation at the hands of the in crowd, seek revenge with the religious fervor of ancient Osiris.

Upon visiting the TOD page and reading some 80 smugly dismissive comments, we found this ever-so-revealing exchange re: the Journal Science:

"They rejected my Energy and Water paper because it didn't fit the interests of their general audience..."

"More likely because it was of too good for them. See my post just above. These "prestigious" journals come up with all sorts of standard lies for rejecting genuinely groundbreaking things. Don't waste your time with them!"

In the feverish jockeying for energy prestige and position, we expect to see the debunkers out in force. They are threatened by new technology suddenly uncloaked that they cannot control. They are angry at the loss of dominion. They tremble at the cracking of their great walls. But those walls crumble each day. And with them the lies and manipulations that have kept so much knowledge locked away from the hands of men. Their day is nearly done. And like many rejected priests - they are hastily unhappy and not amused.

Thanks for the link, it was interesting and informative as well as amusing.

Unfortunately, fakebreaker reply was only amusing. The information is not locked away it is in books that fakebreaker is too lazy to pick up. No engineer feels threatened by new technology that violates the laws of thermodynamics.

This is great! I follow this Hydrogen topic closely. It is the future and I am delighted! A least once a week I post the news to the above blog and people are very interested. Mostly in the cost and the possibility of producing their own fuel. Congratulations

Researchers at MIT must predict marvelous breakthroughs in order to get next years grant so that they can continue to eat breakfast. Solving the hydrogen problems is not a goal any research lab has because it would end their grants. Fusion is the best example of continuing grants for nearly impossible methods. More actual fusion has been done in table top hirsh-farnsworth fusors, but no method produces net energy.

If solar energy were so cheap, more states than Hawaii would require it for water heating which is presently the least costly most effective use of solar. But in an area of execess solar energy an Arizona hospital dismantle their solar thermal collectors? Check Bubble aAtion Pump if you actually want to use solar energy instead of waiting for solar hydrogen. ..HG..